Versatile, precise, and cost-effective

Versatile, precise, and cost-effective: Overmolding is one of the most frequently used processes in the plastics industry and enables the rapid and economical manufacture of components and assemblies. Thanks to its many years of experience with a wide product range, Greiner Assistec is a pioneer in the industry.

Overmolding involves taking a previously manufactured injection-molded part – known as the pre-molded part – and adding a second layer in an additional process step. Cords can be inserted as well as plastic parts: by hand, semiautomatically, or fully automatically. Depending on the chosen plastics, different plastic parts or assemblies can be produced. Examples include: multicolored molded parts made of the same type of plastic but in another color (e.g., control buttons); movable joints made of different plastics – as used in toys with movable arms; or hard–soft connections made of hard base plastics onto which an elastic material is injected, such as in connector housings with injection-molded seals.

Our services are focused entirely on our customers’ needs – and this applies to production, too. Whether the process is manual, semiautomatic, or fully automatic, we adapt to suit the desired requirements in terms of quality and cost. In this way, we are always able to offer the best value for money.

We also always keep our customers’ requirements in mind in our use of tools and machines. Our machines have at least two independently controllable injection units, which allows us to use two or more materials simultaneously in the Injection molding process. The machines are often specially designed for a particular application. It goes without saying that we work closely with the manufacturers of both molds and machines.

The advantages:


  • Manual as well as semiautomatic and fully automatic solutions for overall cost optimization
  • Plastic parts
    • are more resistant
    • are more watertight
    • exhibit higher chemical resistance
  • Different textures
  • Soft finishes for improved handling and feel
  • Tough surfaces for greater durability
  • No sharp edges
  • Good insulating properties

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Best-practice example

An excellent example of the successful application of the overmolding process can be seen in a Greiner Assistec project in the automotive sector. The team worked closely with the customer to develop a wind deflector in which the net is glued onto a bought-in stainless steel frame, then dried and trimmed before insertion into the Injection molding machine, where it is overmolded and thus sealed. The combination of metal and plastic makes the wind deflector especially robust – and using plastic helps to reduce the weight of the end product.

Find out more in our online magazine.